The use of TAB tape leads in automated integrated circuit placement is well known. The use of such TAB tape leads facilitates the automation of the process of electrically connecting integrated circuits to the substrate upon which they are placed.
Typically, an integrated circuit is positioned upon the holding chuck of an inner lead bonder and held in place by a vacuum. Then, a section of TAB tape having the leads required for electrical interconnection of the integrated circuit to the substrate is positioned immediately above the integrated circuit. The leads inside the window of the TAB tape are properly positioned above the bumps of the integrated circuit and bonded to them. TAB tape with the integrated circuit undergoes electrical and burn-in test if required. The leads thereof are excised and formed so as to contact the interconnection pads of the substrate upon which the integrated circuit is disposed. An integrated circuit is positioned via an automated or manual placement device upon the substrate and bonded to it. The leads thereof are bonded to the electrical interconnection pads of the substrate.
Thus, the use of TAB tape provides a means for facilitating automation and burn-in testing of the integrated circuit placement and interconnection processes.
However, a problem frequently encountered in the use of such TAB tape leads is undesirable bending or movement of the leads formed upon the TAB tape during the excise and form operations, integrated circuit placement, and lead bonding. During TAB tape fabrication the leads are maintained in position via a center support. The center support comprises the central portion of the TAB tape site window where the leads converge. The center support must be removed to facilitate the excise and form operations, integrated circuit placement, and lead bonding.
As will be appreciated, such undesirable bending or movement of the leads may result in misalignment thereof, thus resulting in improper connection thereof to the integrated circuit. Thus, it is beneficial to maintain the leads in their proper positions so as to assure reliable interconnection of the integrated circuit with the substrate upon which it is placed via the TAB tape leads.
Thus, the TAB tape leads are particularly susceptible to such bending or movement proximate the center support thereof, after the center support has been punched or cut away. After removal of the center support, the ends of the TAB tape leads along the cut, i.e. the opening, formed by removal of the center support, are free to move.
The prior art has found it beneficial to form a keeper bar upon the TAB tape leads proximate the center support, such that when the center support is removed therefrom, the keeper bar maintains the position of the leads during the excise and form operations, integrated placement, and lead bonding. However, such prior art keeper bars are formed during fabrication of the TAB tape either by mechanical punching (commonly utilized for three layer tape) or by etching (commonly utilized for two layer tape ). However, it would be beneficial to provide a process for forming keeper bars of a desired smaller configuration upon TAB tape during to the TAB tape fabrication process.